Existing image mosaic systems exhibit the defect of blind area, which causes blind spots in the monitoring system, leads to information loss, and poses a threat to monitoring security. In order to eliminate the mosaic area resulting from the processing by the image mosaic system, a new mosaic pattern without splicing the blind area is proposed in this work. First, the advantages and disadvantages of the image stitching layout patterns with and without stitching blind areas are analyzed. Second, using the image mosaic of the images obtained from three uncooled longwave infrared cameras as an example, the design and analysis of the uncooled longwave infrared camera lens is carried out. Finally, in order to obtain a better stitched image, a corresponding treatment measure is provided for the distortion of infrared cameras.